The appliance according to the invention serves for cardiopulmonary massage and/or resuscitation of a patient and is provided with a massage device (17) which can be driven reversibly by a drive device (18) in an actuation direction (23) and which has a pressure area (20) that can be positioned on the chest (12) of a patient (11) at a target contact area (21). In order to ensure that deviations of the pressure area of the massage device from a target pressure point can be determined promptly and reliably, the invention proposes a position sensor device (22), for determining changes in the position of the massage device (17) and/or of the pressure area (20) thereof relative to the target contact area (21) on the chest (12) of the patient in a plane normal to the actuation direction (23) of the massage device (17).